Energy storage system for photovoltaics – is it worth the investment?

Energy storage is increasingly at work in the homes of Polish prosumers. With the rapid development of photovoltaics, there is a growing demand for efficient electricity storage solutions, and this innovative technology is becoming a key tool to increase the efficiency of renewable energy use and generate higher profits, especially after the introduction of net-billing.

Energy demand in homes varies depending on the time of day, which often interferes with the optimal time for photovoltaic panels to generate energy. In particular, photovoltaic installations reach their highest efficiency in the summer and around noon, while home users use the most energy in the morning and evening, especially during the winter season. In such cases, energy storage and maximization of autoconsumption from PV installations play an important role.

There are currently three main systems available for storing energy from photovoltaic panels. The first is the net-billing system, which has replaced the net-metering system. Under net-billing, surplus energy is fed into the electricity grid and billed based on market prices, and from 2024 on an hourly exchange rate. Although this system has its advantages, in the context of energy storage it is less favorable than the previous system of discounts.

The second is to maximize the adjustment of domestic consumption to the energy produced. This means increasing the current consumption of photovoltaic electricity through the use of various devices, such as heat pumps or electric car chargiations. Such a system is more beneficial than sending energy back to the power grid, as it allows more of the produced energy to be used for personal consumption.ng st

The third system is to store excess solar energy using a separate device (such as batteries for photovoltaics) or a set of devices. These solutions make it possible to store surplus energy in any form and use it in times of higher electricity demand.

In this article, we will take a look at energy storage and present its remarkable benefits in the context of photovoltaic installations.

Energy storage system – what is it?

Energy storage allows you to store surplus power when the production of electricity by PV installations outweighs its consumption. In this way, the stored surpluses can be used at times of increased consumption.

Several benefits can be achieved with energy storage. First, by having a storage facility, it is possible to retain the energy produced. When the owner of a photovoltaic system does not use the storage facility, the surplus electricity produced is returned directly to the power grid under established billing terms. In contrast, thanks to the storage facility, all energy remains at the owner’s disposal. Secondly, energy storage provides energy independence. It protects the owner from power outages, making the household, farm and enterprise immune to power failures, weather anomalies and other unexpected events.

How does it work?

Energy storage works by converting solar energy into electricity using photovoltaic panels. The cells in the panel convert sunlight into electricity in the form of direct current (DC), which then flows to an inverter, where it is converted into alternating current (AC), which can be used to power household appliances. If the demand for electricity at home is less than the energy generated, the DC current can be drawn from the photovoltaic panels and used to charge the energy storage. Once the batteries are fully charged, any surplus is sold to the power grid. At night, when the house needs electricity, the battery discharges to power appliances and devices, so you can use renewable energy even after the sun goes down.

A key component of the energy storage is the Battery Management System (BMS), which monitors parameters such as voltage, current, temperature and state of charge. The BMS is responsible for the safety and efficiency of the battery, controlling the charging and discharging processes and protecting the battery from dangerous conditions such as overcharging, discharging or overheating.

Types of energy storage systems

Among others, we distinguish the following types of energy storage:

• Lithium-ion batteries: the most popular type of energy storage. They have high efficiency and can be discharged almost to zero. There are different types, such as NMC, NCA, LTO, but for stationary storage, LFP batteries are commonly chosen for their high level of safety.
• Lead-acid batteries: this is an older technology that is popular for small off-grid installations due to its resistance to cold. Although cheaper than lithium-ion, they have lower efficiency and cannot be discharged below 50% state of charge. They are less efficient and require a separate room with ventilation.
• Flow storages: are an alternative option with slower degradation, lower costs and greater environmental friendliness compared to lithium-ion batteries. Currently, they are mainly used in industrial installations due to their larger size and power. However, their popularity in domestic installations may increase in the future.
• Hydrogen energy storage: this is a completely different class of storage. They have a long life and are environmentally friendly. However, their low efficiency and high cost currently limit their widespread use. However, they are expected to gain popularity in the future as prices drop and technology advances.

Choosing the right type of energy storage depends on individual needs, budget and user expectations. Each type has its own advantages and limitations, so it is important to thoroughly understand their characteristics before making a decision.

Benefits of having energy storage system

Magazyny energii w instalacjach fotowoltaicznych oferują szereg korzyści, przyczyniających się zarówno do większej niezależności energetycznej użytkowników, jak i do transformacji energetycznej w systemach bardziej zrównoważonych i ekologicznych.

• Increased self-consumption of energy: using more of the renewable energy produced directly in the home, leading to less dependency on purchasing energy from the supplier.
• Energy independence in the event of a failure: in the event of a power outage from the grid, energy storage can provide an independent power source, enabling the continued operation of key equipment and systems.
• Financial savings: increased self-consumption of energy and the ability to sell surplus energy to the grid translate into lower energy bills and potential profits from self-generation.
• Ecology and sustainable development: the use of energy storage contributes to reducing greenhouse gas emissions and increasing the share of renewable energy in the overall energy mix, contributing to environmental protection and sustainable development.
• Flexibility and access to energy at any time: energy is collected at any time, allowing users to use it at a convenient time, regardless of weather conditions or time of day.
  Ability to use energy from the grid and optimize tariffs: Some energy storage systems allow users to take energy from the grid during periods of lower tariffs, which contributes to greater financial savings.
• Optimal management of the power grid: storing surplus energy and using it in times of higher demand, which reduces the load on the network and contributes to greater stability and efficiency of the power system.

Summary

Energy storage facilities allow prosumers to store excess energy produced, which is extremely beneficial during periods when energy production exceeds demand. This makes it possible to achieve near-complete energy independence, using stored energy at times of lower sunlight or highest demand. This means that you can maximize the self-consumption of renewable energy, that is, the direct consumption of energy in the home. Properly designed and configured energy storage enables optimal energy management, contributing to greater energy independence for the prosumer.

Sources:

https://enerad.pl/magazyny-energii/

https://fotowoltaikaonline.pl/magazyn-energii#zasada-dzialania